Herpes sores usually appear as one or more blisters on or around the genitals, rectum or mouth. The blisters break and leave painful sores that may take a week or more to heal. These symptoms are sometimes called “having an outbreak.” The first time someone has an outbreak they may also have flu-like symptoms such as fever, body aches, or swollen glands.

“Herpes is caused by sexual intimacy and contact with a person who is actively shedding the herpes virus,” says Cullins. If you have HSV-1, that shedding could happen through the mouth or a cold sore, which means that the virus can be transmitted through kissing, or just sharing a drink. If you have herpes that affects the genitals, it can be transmitted from sharing sex toys, grinding, or even mutual masturbation — any activity where the virus can be transmitted from one person to another through skin-to-skin or mucosal contact.
As with almost all sexually transmitted infections, women are more susceptible to acquiring genital HSV-2 than men.[41] On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is about 8–11%.[37][42] This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is around 4–5% annually.[42] Suppressive antiviral therapy reduces these risks by 50%.[43] Antivirals also help prevent the development of symptomatic HSV in infection scenarios, meaning the infected partner will be seropositive but symptom-free by about 50%. Condom use also reduces the transmission risk significantly.[44][45] Condom use is much more effective at preventing male-to-female transmission than vice versa.[44] Previous HSV-1 infection may reduce the risk for acquisition of HSV-2 infection among women by a factor of three, although the one study that states this has a small sample size of 14 transmissions out of 214 couples.[46]
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The causes of reactivation are uncertain, but several potential triggers have been documented. A 2009 study showed the protein VP16 plays a key role in reactivation of the dormant virus.[71] Changes in the immune system during menstruation may play a role in HSV-1 reactivation.[72][73] Concurrent infections, such as viral upper respiratory tract infection or other febrile diseases, can cause outbreaks. Reactivation due to other infections is the likely source of the historic terms 'cold sore' and 'fever blister'.
While some people realize that they have genital herpes, many do not. It is estimated that one in five persons in the United States has genital herpes; however, as many as 90 percent are unaware that they have the virus. This is because many people have very mild symptoms that go unrecognized or are mistaken for another condition or no symptoms at all.
"Oral herpes is an infection found in the mouth, or on and around the lips, caused by the Herpes Simplex Virus (HSV)," Michael explains. "There are two types or strains of this virus called HSV1 and HSV2. Usually, the HSV1 strain infects the mouth and lips, and the HSV2 strain infects the genitals. It is however possible for HSV2 to infect your mouth and lips."
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